Device for unstacking containers

ABSTRACT

An arrangement ( 1, 1 ′) for automatically unstacking containers ( 6, 6 ′) nested in each other in lying posture, by depositing them on a support, e.g. a conveyor ( 3   a ), with the container opening ( 6   a ) facing upwards, the arrangement comprising a gripping device ( 5 ) for gripping and moving out the respective first container ( 6 ) of a lying container stack ( 2, 2 ′), the gripping device ( 5, 5 ′) being arranged on holding elements ( 8   a   , 8   b ) movable in stacking direction, and further comprising a clamping device ( 4 ) for holding back the lying container stack ( 2, 2 ′), with the foremost container ( 6 ) being left free, wherein the gripping device ( 5 ) is provided with lateral pressure-medium cylinders ( 5   a   ; 46 ) which have horizontal axes on the same level and which are connected with the holding elements ( 8   a   , 8   b ) extending thereabove.

The invention relates to an arrangement for automatically denestingcontainers in lying position and nested in each other, the containersbeing deposited on a support, e.g. a conveyor, with the containeropening facing upward, the arrangement comprising gripping means forgripping and moving out a respective first container of a lyingcontainer stack, the gripping means being arranged on holding elementsmovable in the direction of the stack, and further comprising clampingmeans for holding back the lying container stack, with the foremostcontainer being left free.

Containers which as a rule have frusto-conical shapes, i.e. have obliquewalls, are stored in stacks in warehouse stocks or in commissioningsystems, e.g., and they must be denested again before use and suppliedindividually for filling. Denesting should occur rapidly and gently and,in particular, it should be automated since the individual containersare supplied to conveying means in intermittent manner, and manualdenesting would be very laborious.

In DE 3 042 903 A, automatic denesting has been described. Here, alifting mechanism is provided which engages the respective uppermostcontainer of a vertical container stack advanced on a conveyor belt,which lifts this uppermost container and which deposits it on a conveyorbelt. What is of disadvantage is that the lifting mechanism isrelatively complex in construction, primarily since it must engagecontainers at ever changing levels; moreover, the vertical containerstacks pose problems if they have to be advanced over larger distancessince, in case of major stack heights, they have little stability andtopple easily if their movement is started or stopped with jerks.

According to U.S. Pat. No. 4,915,578 A, a vertical container stack istop-delivered to a holding device, the lowermost container being leftfree so that it drops onto a conveyor belt provided therebelow and ismoved off by aid of the same. In detail, two oppositely arranged flangerims of the containers lie on projecting tooth ledges of a chain, whichtooth ledges guide the containers downwardly in still stacked manner. Bymeans of projections engaging the two oppositely arranged rims of thelowermost container from above, a second chain moving faster and incounter-direction pushes this lowermost container from the stackdownwards to below so that it drops to the conveyor belt at last and istransported away. Here, too, it is a disadvantage that the stack isprovided vertically, with the risk of tilting, as already describedbefore, primarily in case of major stack heights. Moreover, the devicesused must be built high, increasing construction costs. The containerstack must not exceed a certain height also because otherwise it wouldbecome too heavy and the stack could no longer be carried by the device.

In U.S. Pat. No. 4,983,098 A, an arrangement of the present type isdescribed, for providing cup-shaped conical containers individuallybefore they are filled and closed, the containers being delivered invertical stacks which are turned over. From the lying container stack,the foremost container is gripped by vertically movable lug memberswhich then are moved horizontally together with the foremost containerso as to pull it away from the remaining stack. At the same time, thesecond container is held back by like, vertically movable lug members.To be put into an upright position, the foremost container moves againsta pivotable hook member which grips the upper container rim at its innerside so that the container is decelerated at its upper rim while it istransported on on the conveyor; this results in upright tilting of thecontainer. A disadvantage is that the lug members which engage behindthe container rims with one of their legs must be precisely adapted tothe containers and that their vertical movement requires a relativelycomplex driving means which in parts must be mounted laterally of theconveyor.

In U.S. Pat. No. 4,054,212 A, finally, an arrangement for downwardlytilting cup-shaped containers, bottoms first, is described, wherein thisdenesting should be effected in an automatic drink dispenser. The cupsare pushed forwards by pivotable ram arms via arcuate rails until theyfall into a holding means on a conveyor. At the same time, the secondcup of the stack is kept back by gripping fingers. This construction isprovided for denesting cups, and it is hardly suitable for containers ofsubstantially larger mass.

It is an object of the invention to provide an arrangement fordenesting, as initially indicated, with which it is possible to denestnested containers in a rapid and reliable manner, by using simpleconstruction measures, as well as with a high flexibility as regardscontainer dimensions.

The arrangement according to the invention of the initially defined kindis characterized in that the gripping means is provided with lateralpressure-medium cylinders which have horizontal axes on the same leveland which are connected with the holding elements extending thereabove.Because of the lying posture of the container stack, the structuralheight of the arrangement can be a low one, and also the containers neednot be lifted or need be lifted only slightly. Thus, the“overhead”-arrangement of the holding elements does not pose anyproblems. The use of pressure medium cylinders for the gripping meansallows for a simple mode of construction, while nevertheless an easy,reliable and rapid gripping of the foremost container is possible. Sincethe pressure medium cylinders have horizontal axes on the same level,the foremost container is tightly held between the pressure mediumcylinders, with the containers neither tilting nor sliding off-center.

The entire lying or horizontal container stack can be lifted from itssupport by a lifting mechanism before the foremost container is movedon, the lifting mechanism being capable of reaching between rollers of aroller conveyor provided as support, e.g.; the lifting mechanism may,however, also be built with rails or lifting ledges engaging laterallyon the lower side of the container stack, in which case the stacksupport may also be formed by a conveying belt. Lifting of the containerstack reliably prevents frictional sliding of the first container alongthe support while it is being pulled away from the container stack.Apart from the fact that the containers and the conveyor are carefullytreated thereby, in this manner the amount of energy employed isminimized.

The pressure medium cylinders provided according to the invention mayengage the respective container frictionally or positively, and suitablythey are simply released from the container after the respectivecontainer has been moved away from the remaining stack and after it hasbeen pivoted, and thus this container is simply dropped onto itssupport; the dropping height may be low so that a gentle “depositing” ofthe containers nevertheless is ensured. The pressure medium cylindersare to be designed such that they are capable of transmitting therespective transverse forces; optionally, also a lever mechanism can beprovided. For pivoting of the containers while providing themindividually, it is particularly advantageous if the pressure mediumcylinders are rotatably arranged on the holding elements.

It is particularly advantageous if the holding elements are mounted tobe linearly displaceable in parallel to the container stack. In thismanner, the foremost container is linearly moved away from the remainingcontainer stack. The foremost container suitably is gripped at itsopening rim or collar facing rearwards, and is pushed from the containerstack with its bottom facing forwards, the container bottom of theforemost container at least in the starting phase of pushing from thestack being located at a distance above the support so that thecontainer does not chafe on the support.

The pressure medium cylinders, or their piston rods, respectively, maybe oriented coaxially, and may be provided with a rubber head or thelike with which they can be pressed softly against the container andsafely against slipping aside therefrom. In the case of rotatablepressure medium cylinders, simple pivoting of the foremost containerabout the horizontal axis of the pressure medium cylinder into asubstantially horizontal position is enabled, i.e. with the openingfacing upwards, wherein only the pressure medium cylinders carry out arotational movement and other parts of the gripping means would not haveto be rotated.

Moreover, it is advantageous if the holding element, e.g. the legs of aframe, are mounted on a linear guide. In this case, a pressure mediumcylinder may press the frame in the direction away from the containerstack, and by the frame it is ensured that both sides of the containerwill be gripped and moved simultaneously, whereby the container willremain exactly straightly aligned and not get stuck by jamming, e.g.because of a slight turning out of this longitudinal alignment on thecontainer stack.

For a simple depositing of the containers, it is particularlyadvantageous if the support receiving the denested containers ispreceded by an edge provided at a higher level relative thereto, fortilting of the individual containers. After the foremost container hasbeen moved out of the container stack as described above, it is moved inlying posture, with the container bottom facing forwards, to the edge,and there it is released for turning by tilting about this edge and fordeposit on the support following the edge, e.g. a conveyor. In thiscase, the container must be pulled away from the next container merelyby a short distance, and it can be guided to the edge by means of aconveyor, e.g. a conveyor belt or a roller conveyor. As soon as asufficiently large part of the container projects beyond this edge, itwill tilt, as a consequence of gravity, with the container bottomdownwards to the support located at a somewhat lower level, and there itcomes to stand upright. From there it will be led away immediately tomake room for the next container. The edge will be provided as close tothe denesting arrangement proper as possible, so that the individuallying container need not be transported far before it tilts onto thesupport. In terms of construction it is also possible to make the heightdifference of these two supports adjustable, e.g. in that theconsecutive support is shiftable in terms of height, or in that it ismounted to be pivotable about an axis, wherein, optionally, an ascent ora descent is brought about. In this manner, differently sized containerscan be provided individually. To avoid rubbing of the containers alongthe support, the pressure medium cylinders here preferably are notrotatable, but fixedly mounted on the holding elements, and thus theycarry the entire mass of the container.

A further preferred arrangement is characterized by a cam control forthe holding elements so as to move the foremost container according to apredetermined, in particular arcuate, movement out of the containerstack and deposit it on the support, e.g. the conveyor, by pivoting itinto a position with the container opening facing upwards. The amount bywhich the container is lifted will depend on the depth of the container.In any event, by the pivoting movement, slipping of the container on thesupport and thus an increased frictional resistance can largely beavoided. The container openings of the containers in the lying containerstack may face forwards, whereby pulling out and turning of therespective foremost containers can be realized particularly simply inone single, continuous movement. Yet the containers may also be providedwith the container bottom facing forward, in which case pivoting of thecontainer will be caused only after the foremost container has beenpulled away from the stack.

As has already been suggested, in the last-mentioned embodiment, it isadvantageous for minimizing movement during denesting if the foremostcontainer is moved away from the lying container stack with its openingfacing forward. While the foremost container is moved out and upwards,it will tilt automatically into a position with the container openingfacing upwards, most simply by the container's center of gravity beingarranged behind or below the point of engagement of the gripping meanson the container, whereby the container seeks to assume the lowermostposition.

To controlledly pull the foremost container out of the container stackit is also advantageous if the holding elements, e.g. the legs of aframe, are pivotably mounted. In this manner, the various individualmovements of the foremost container will be combined and coordinatedwith each other in a very simple manner: At the same time as the firstcontainer is pulled out of the container stack, the axis of the pressuremedium cylinders and thus also of the containers is arcuately movedforward and upwards by the pivotal movement of the holding elements,which movement is assisted by the oblique container walls, since in thismanner, frictional slipping of the container on the support isprevented; when pivoted further, the container finally assumes itsposition with the opening facing upwards.

The holding elements may also have an associated connecting-link guideor a four-bar linkage for control of their movement. The movement of theholding elements and, thus, of the containers may be optimized so thatmerely minimal lifting of each foremost container is effected while itis being pulled away from the stack, without lifting the container foran unnecessary large distance to then lower it immediately thereafterand to put it onto the support.

To efficiently effect the translation or pivotal movement of the holdingelements, preferably pressure medium cylinders are provided as drive forthe holding elements.

To grip the foremost container particularly tightly, it is advantageousif the gripping means comprises gripping jaws to be pressed against thecontainer, which are attached on pivoting levers engaged by the pressuremedium cylinders. The pivoting levers in this case are pivotablymounted, e.g. on brackets fixedly attached on the holding elements. Byactuating the pressure medium cylinders, the pivoting levers are pivotedabout their pivot axis, and thus the gripping jaws are pressed againstthe foremost container. Should the foremost container be jammed in thenext container, the gripping jaws are further pivoted by the forwardmovement of the holding elements and pressed more tightly against theforemost container. This increases the pressing effect, and the foremostcontainer will reliably be moved out of the container stack.

To pull the first container out of the container stack, a particularlysimple construction becomes possible if the clamping means contains apressure medium cylinder which presses at least the second container inthe stack downwards, preferably in combination with a lifting mechanismwhich lifts the entire lying container stack.

To ensure a safe positioning and holding back of the container stack,the clamping means may also have an associated stop for the containerstack, which stop can be moved out of the way of the containers, e.g. bypivoting. The arriving container stack is stopped by the stop atprecisely the correct position for clamping retention. Whilesubsequently the gripping means grips the foremost container, the stopcan, quickly be moved out of the way, e.g. by pivoting, so that removalof the foremost container from the container stack will not be impededthereby. After this container has been removed, the stop can beactivated again so as to stop the remaining container stack, which hasbeen moved forward in the correct position regarding the clamping means.It is also possible that one stop is provided on each lontigudinal sideof the container stack on the support, e.g. on the conveyor.

Moreover, it is also advantageous if a trigger photoelectric barrier isprovided for actuating the pressure medium cylinder and/or the stop. Inthat case, the trigger photoelectric barrier exactly controls thetemporally correct actuation of the pressure medium cylinder and or thestop, respectively, if the container stack is moved forwards in eachinstance. The trigger photoelectric barrier may, e.g., be provided onthe support in the region of the lifting means or laterally on thestand.

It is also advantageous if a monitoring photoelectric barrier isprovided for sensing the remaining containers of the stack. With this,the clamping means can be switched off if all the containers of a stackhave been provided individually, and/or a further container stack can berequested in time.

Optionally, a vertical container stack may be turned over to thehorizontal on a conveyor prior to denesting, so as to provide thecontainer stack in lying posture. In this manner, the containers maypreviously be stacked to a vertical container stack which, as a rule, iseasier than stacking in lying posture. For denesting, suitably alreadyturned, lying container stacks are supplied so that their advancing canbe effected without any problems, wherein also several turned containerstacks may be slid into one another prior to denesting.

Accordingly, it is suitable if the gripping means is preceded by apneumatically actuated stack turning device. Thus, stacking of thecontainers may be effected in vertical state and denesting them in lyingstate. By the pneumatic actuation, simple control and reliablefunctioning of the stack turning device is achieved.

A stack turning device of advantageous function is obtained if itcomprises a stack sliding support which is vertical in the restingposition and is pivotable about a horizontal axle. The verticallyupright container stack leans against this sliding support. The slidingsupport is at least as long as the container stack is high so as tosupport the latter during the turning movement. The sliding supportpivots, e.g. by aid of a pressure medium cylinder, about an upperhorizontal axis, the lower end moving the lowermost containers of thecontainer stack out of the upright position so that the stack begins totilt. For a minimum force to be applied, the axle about which thesliding support tilts is provided in the upper region of the slidingsupport, whereas the pressure medium cylinder driving it engages as lowon the sliding support as possible, whereby the lever action is bestutilized. The container stack is supported by the sliding support whilebeing turned to a lying posture, the pivot movement of the slidingsupport being continued such that both the sliding support and thecontainer stack assume an ever more slanted position, yet with thelowermost container always remaining in “bottom” contact (with theconveyor). As soon as a certain minimum inclination has been attained,the container stack will slide down along the sliding support and thuswill come to lie. Such sliding is assisted by a guided movement of thelowermost or foremost container, respectively, on the support, e.g. bythe support being a driven conveyor, e.g. a conveyor belt. The lattermay immediately transport away the lying container stack so as to makeroom for the next container stack. The next upright container stack isbrought to the turning device by a conveyor so that the stack againabuts on the sliding support which meanwhile has been pivoted back intoits starting position.

A particularly advantageous construction provides that a roller isprovided opposite the sliding support on a stand, which roller forms astack stop when turning the stack into the horizontal position. Thisroller may be mounted on a transverse beam of the stand so that theupper stack region abuts on the roller and is held back by the latterwhile the sliding support carries out its pivotal movement. Also severalrollers mounted on the stand in spaced-apart relationship would beconceivable.

A simple, efficient construction is also obtained if the stack turningdevice comprises angled forked arms mounted so as to be pivotable abouttheir horizontal angle axis. In that instance the—vertical—containerstack is pushed onto the one fork arms until it comes to abut on theupright second fork arms provided approximately at right angles to theformer. The upright fork arms subsequently are pivoted into thehorizontal, thereby acting as support for the stack which simultaneouslyis held by the other, originally horizontal fork arms, which are tiltedup into a vertical position, so that in doing so, the stack is alwayskept and manipulated under control.

A particularly preferred construction is characterized in that the stackturning device comprises supporting devices for the container stack,which are movable relative to each other and which have associatedseparate pressure medium cylinders for their independent pivotalmovement. These supporting devices may, e.g., be two pairs of fork armswhich are pivotable upwards and downwards independently of each otherabout a mutual horizontal axis or about separate horizontal axes oftheir own, in the region of the support, i.e. the conveyor.

For a continuous operation of the automatic denesting, a containerrotating device for rotating the denested box-type containers from theirtransverse orientation into a longitudinal orientation is advantageous.In this manner, the containers are automatically moved on in thelongitudinal orientation usually desired in commissioning systems, e.g.,and this even if the containers are obtained in transverse orientationafter denesting, which frequently will be the case since with lyingstacks, for reasons of stability the containers will arrive with theirlarger side face lying on the conveyor.

For use in commissioning systems, it is also advantageous if thecontainer rotating device has an associated control unit for rotatingeach container with a pre-determined side facing forward. Incommissioning systems, in most instances the front walls of thecontainers carry documents, codes etc. which are important for thecontrolled movement of the container through the commissioning systemand for its filling. In that instance, reading units are provided in thecommissioning system for the proper function of which the correctorientation of the containers is important.

A particularly simple construction of the rotating device consists inthat it comprises two stops, e.g. cylinders, adjacently arranged on theconveyor provided as the support and selectively projectable across theconveying plane, after which the conveyor preferably narrows. Dependingon the direction in which the container is to be rotated, one or theother cylinder lowers so that it no longer projects from the conveyingplane. The container which has been advanced is stopped on one of itssides by the one projecting cylinder, while the other side of thecontainer is moved on by the conveyor. This results in a rotation of thecontainer about the protruding cylinder, past which it is guided. Theguides on both sides of the conveyor narrow in transporting directionuntil the distance between them allows only the passage of alongitudinally oriented container. In this narrowed portion, thecontainer which has already been rotated to some extent is forced to acomplete longitudinal orientation.

As has already been mentioned, according to the present invention stacksof differently high containers can be denested without any problems. Forthe differently high containers subsequently being specifically usablefor their respective tasks, they have to be distributed according totheir heights. Accordingly, preferably a shunting means is provided fordistributing the individually provided box-type containers to variousconveying paths, e.g. in accordance with their container height. In mostinstances, two consecutive conveyors will be present, at least onepivotable lever or pivot arm in each case merely leaving the desiredconsecutive conveyor accessible by which the container is to beconveyed, and blocking access to the other consecutive conveyor.

For a simple recognition of the container height of the container whichhas just arrived, it is advantageous if the shunting means has apreceding container height sensor, e.g. with photoelectric barriers atdifferent levels. If a container of a certain height is moved past thesensor, the latter senses this and transmits a signal corresponding tothe sensed container height, for pivoting the lever or pivot arm into acertain position.

In the following, the invention will be further explained by way ofpreferred exemplary embodiments illustrated in the drawings to which,however, it shall not be restricted. In detail,

FIGS. 1a to 1 d schematically illustrate different phases of theoperation of a particularly preferred arrangement for automaticallydenesting nested containers in side view, the foremost container beingmoved away from the container stack by means of linearly shiftablegripping means;

FIG. 1e shows a schematic end view of the arrangement illustrated inFIG. 1a;

FIGS. 2a to 2 d show in corresponding schematic side views a differentarrangement for automatically denesting nested containers, wherein theforemost container is pulled out of the remaining container stack by agripping means according to an arcuate movement and is deposited on thesupport by being pivoted into a position where the container openingfaces upwards;

FIG. 2e shows a schematic end view of the denesting arrangementillustrated in FIG. 2a, wherein for the sake of simplicity, a stop isshown on the left-hand side of the container stack, yet such a stop hasbeen omitted on the right-hand side of the stack in order toschematically illustrate a part of the lifting mechanism arrangedtherebehind;

FIGS. 3a to 3 d, in four schematical side views, show a stack turningdevice in various phases of its operation when turning over a verticalcontainer stack;

FIG. 3e shows a top view onto this stack turning device;

FIGS. 4a to 4 c in three views corresponding to different phases ofoperation schematically illustrate a variant of a stack turning means, astill upright container stack being illustrated in end view in FIG. 4a,FIG. 4b showing an associated top view, and FIG. 4c, in a viewcorresponding to FIG. 4a, showing the now lying container stack;

FIG. 5a shows a side view of a container rotating means forlongitudinally orienting of the individually provided containers;

FIG. 5b shows a top view onto this arrangement;

FIG. 6 shows a shunting means for distributing the containers accordingto container height to two different consecutive conveyors;

FIGS. 7a to 7 e show views of a particularly preferred stack turningmeans to be used in combination with denesting according to FIG. 1, invarious phases of operation; and

FIG. 8 is a perspective representation of a particularly advantageousgripping means to be used in the arrangement according to FIG. 1.

In FIG. 1, the individual FIGS. 1a to 1 e schematically show anarrangement 1 for automatically denesting or providing individuallybox-type containers of a lying container stack 2 which is supplied inthe direction of the arrow I on a conveyor belt 3 provided as a supporttowards a clamping means 4 of the arrangement 1. By means of lateralpressure medium cylinders 5 a, a gripping means 5 grips the foremostcontainer 6 of the container stack 2 on a collar-shaped rim 7surrounding the container opening, with the container bottom 6 a facingforward. The pressure medium cylinders 5 a of the gripping means 5 havea horizontal axis and are attached on holding elements 8 a, 8 b formedby the legs of a frame 9. The pressure medium cylinders 5 a are mountedon the legs 8 a, 8 b in a per se conventional manner and designed suchthat they are able to accommodate transverse forces when gripping thecontainers 6; alternatively, also a lever mechanism can be providedwhich is actuated by the pressure medium cylinders 5 a and whichaccommodates the transverse forces (cf. also FIG. 7). Frame 9 with itslegs 8 a, 8 b is mounted on a linear guide 10 of an arrangement stand11, this linear guide extending in parallel to the stacking direction ofthe container stack 2. By a pressure medium cylinder 12 fastened to thestand 11 at A, frame 9 is moved in the direction of arrow I, theforemost container 6 being pushed off the container stack 2.

In doing so, the second container 6′ in the container stack 2 is presseddownwards by a clamping pressure medium cylinder 13 fixedly connected tothe stand 11, and thus the second container is prevented from beingpulled off together with the foremost container 6. The foremostcontainer 6 is advanced to an edge 14. This is effected either by aid ofthe pressure medium cylinders 5 a, which only release the container 6 atedge 14, or the pressure medium cylinders 5 a serve merely to pullcontainer 6 out of the container stack 2, whereupon they release it, andthe container 6 is moved on towards the edge 14 by means of the conveyor3. At edge 14, the container 6 tilts downwards due to gravity with itsbottom 6 a first (cf. FIG. 1c), the pressure medium cylinders 5 areleasing the container 6 so that the container 6 comes to stand uprighton a support, e.g. a conveyor 3 a, with its opening 6 b facing upwards,from where it is transported away. If transporting away on the conveyor3 a is transversely to the conveyor 3, a guide or a stop 15 may bepresent on conveyor 3 a so that container 6 which has been tilted downcomes to stand on the conveyor 3 a in an aligned position. Stop 15 alsoprevents further tilting or turning of container 6.

When the pressure medium cylinders 5 a have released container 5, theframe 9 with its legs 8 a, 8 b (cf. FIG. 1e) is moved back again in thedirection of arrow II (cf. FIG. 1d) so that the pressure mediumcylinders 5 a are able to grip the next container 6′ in the containerstack 2, if the container stack 2 is advanced by a correspondingdistance, the second container in stack 2 then again being held tightlyby aid of the (pneumatic) clamping pressure medium cylinders 13 of theclamping means 4. The previously described process is repeated until theoriginally second container 6′ has been tilted onto the conveyor 3 a,etc.

In FIGS. 2a to 2 e, illustrations corresponding to those of FIGS. 1a to1 e show a further denesting arrangement 1′. Here, too, a lyingcontainer stack 2′ is provided, yet the containers, e.g. 6, are suppliedto the arrangement 1′ by a conveyor 3 in the direction of arrow III withtheir opening 6 b facing forward. Pressure medium cylinders 5 a of agripping means 5, which again have horizontal axes and are mounted onholding elements 8 a′, 8 b′ (cf. also FIG. 2e) again grip the formostcontainer 6, e.g. at its collar-shaped container rim 7, yet here so asto move it out of the container stack 2′ according to an arcuatemovement (cf. FIGS. 2b and 2 c) and to deposit it again on the conveyor3 (or a consecutive conveyor), by pivoting it into a position with thecontainer opening 6 b facing upwards (cf. FIG. 2d).

The pressure medium cylinders 5 a of the gripping means 5 comprisehorizontal axes and are rotatably mounted on their holding elements 8a′, 8 b′, which again are formed by the legs of a bow-shaped frame 9′(cf. also FIG. 2e); frame 9′ itself in this case is mounted in thearrangement stand 11 so as to be pivotable on its upper side at B (cf.FIG. 2a); as pivot drive, again a pressure medium cylinder 12 isprovided, which is mounted at A on a transverse bar of the stand 11(FIGS. 2a, 2 d and 2 e). This pressure medium cylinder 12 pushes frame9′ with its legs 8 a′, 8 b′ forwards in the direction of arrow IV (cf.FIGS. 2b and 2 c) so that frame 9′ together with the pressure mediumcylinders 5 a carries out an arcuate movement (cf. arrow V in FIGS. 1band 1 c), whereby the foremost container 6 a is pulled out of thecontainer stack 2′. In this instance, the end of the piston rod may behinged on a sliding block (not illustrated) shiftable on the frame 9′ interms of height. On account of the eccentric center of gravity of thecontainer 6 behind (below) the point of engagement of the pressuremedium cylinders 5 a on container 6, which pressure medium cylinders 5 aare rotatably mounted on the holding elements or legs 8 a′, 8 b′, thecontainer 6 pivots automatically into an approximately horizontalposition (cf. FIGS. 2b and 2 c), with the container opening 6 b facingupwards.

When the foremost container 6 has been released by the pressure mediumcylinders 5 a and has been deposited on the conveyor 3 with its opening6 b facing upwards, the legs 8 a′, 8 b′ of frame 9′ again pivot backinto the starting position (cf. arrow VI in FIG. 2d) so as to grip thenext container—which had been the second container 6′ before incontainer stack 2′—and the procedure described is repeated after thecontainer stack 2′ has been advanced by a corresponding distance—e.g.equal to a collar height.

For the foremost container 6 not to slip on the support during itsmovement away from the stack 2, or 2′, respectively, a lifting mechanism16 is provided underneath the container stack 2, or 2′, respectively, oneither side adjacent the conveyor 3, cf. FIG. 2a as well as FIG. 2e,right-hand side. This lifting mechanism 16 is designed with rails orlifting ledges 16 a which engage the lateral rims of containers 6 of thecontainer stack 2, or 2′, respectively, from below, which lateral rimstransversely project beyond the conveyor 3, and thus push stack 2, or2′, respectively, upwards. The lifting mechanism 16 thus lifts up thecontainer stack 2, or 2′, respectively, even before the first container6 has been pulled out, and lowers it only after the foremost container 6has been located at a distance from the container stack 2, or 2′,respectively. Suitably, such a lifting mechanism 16 is also provided inthe arrangement 1 according to FIG. 1, yet this has not been illustratedin FIG. 1.

Also according to FIG. 2, furthermore, two pressure medium cylinders 13are provided as clamping means 4 which push downwards the respectivesecond container 6′ in the container stack 2′ and thus clamp it tightly,whereby the second container 6′—and all the following containers ofstack 2′—is/are kept back while the first container 6 is moved out, andis/are not pulled along therewith.

According to the exemplary embodiments according to FIGS. 1 and 2, onepivotable stop 17 is provided on either side of the container stack 2,or 2′, respectively, on the conveyor belt 3. In this manner, thearriving container stack 2, or 2′, respectively, is stopped at preciselythe correct position for the clamping means 4. While the pressure mediumcylinders 5 a grip the foremost container 6, the stops can lowerthemselves, so that pulling the foremost container 6 out of thecontainer stack 2, or 2′, respectively, will not be impeded. During orafter deposit of this foremost container 6 on the conveyor belt 3, or 3a, respectively, stop 17 may be tilted up into its effective positionagain.

Below the container stack 2, or 2′, respectively, a triggerphotoelectric barrier 18 (cf. FIGS. 1a, 1 b and 2 a, 2 b) is mountedwhich temporally controls upward and downward tilting of the stop 17and/or activation of the pressure medium cylinders 12 and 13.

To monitor the remaining containers, furthermore a monitoringphotoelectric barrier 19 (cf. FIGS. 1a and 2 a) are mounted on the stand11 so that it can be sensed automatically as soon as a minimum amount ofremaining containers is fallen short of.

In FIGS. 3a to 3 e, a stack turning device 20 is illustrated, the courseof turning a vertical container stack 2 a into a horizontal positionbeing illustrated in schematical side views in FIGS. 3a to 3 d; FIG. 3eshows a schematical top view of this stack turning device 20 to whichseveral container stacks 2 a, and 2 a′, respectively, are successivelysupplied.

The container stack 2 a to be turned into the horizontal position abutsa sliding support 22 (cf. FIG. 3a) pivotable about an upper axle 21,which sliding support may be a sliding plate or interconnected uprightslide rails. In FIG. 3b the sliding support 22, driven by an e.g.pneumatic, pressure medium cylinder 23, begins to pivot about the upperaxle 21 fixed in the stand, and in doing so it pushes the lower regionof the stack 2 a to the right-hand side according to the illustration inFIGS. 3a to 3 e, until the latter has reached a conveyor 3 b providedfor transporting the stack off; in this instance, the stack 2 a tiltsover and comes to be supported on the sliding support 22; in the upperstack region, a stop is being contacted which is formed by a roller 25mounted on a transverse beam 24 of the stand not further denoted indetail. Conveyor 3 b pulls away the lower region of the container stack2 a in the direction of arrow VII (cf. FIGS. 3b and 3 c), while theupper stack region abuts on roller 25 and is held back by the latter,and while the pivoting movement of the slide support 22 continues sothat the container stack 2 a assumes an ever more inclined position.Finally, the container stack 2 a slides downwards along the slidingsupport 22 until the uppermost container has passed the end of thesliding support 22 and the stack comes to lie horizontally on theconveyor 3 b with the container bottoms 6 a facing forward, whichconveyor 3 b then further transports stack 2 in the now lying posture tothe arrangement according to FIG. 1 (cf. FIG. 3d). The sliding support22 now pivots into its vertical starting position so as to support thenext vertical container stack 2 a′.

Suitably, the arriving container stack 2 a is moved from the side, via atransverse conveyor 3 c, into the turning device 20 (cf. FIG. 3e) sincethen it is possible to simply mount the sliding support 22 onlypivotably.

In FIG. 4, a different stack turning device 20′ is illustrated, FIG. 4ashowing a side view, and FIG. 4b showing a top view onto the stackturning device 20′ with the still standing, vertical container stack 2a. The container stack 2 a abuts on the perpendicular fork arms 26 andis located on conveyor 3 c, e.g. a roller conveyor, above horizontalfork arms 27 which are arranged approximately at right angles to thefork arms 26. The container stack 2 a may be guided by conveyor 3 c inthis position as far as to the stop on the fork arms 26, or it may beput onto the fork arms 27 in any other manner. The angled fork arms 26,27 form a structural unit and are mounted to be pivotable by about 90°about their horizontal angle axle 28.

The originally vertical, long fork arms 26 are pivoted into thehorizontal to turn stack 2 a in the direction of arrow VIII (cf. FIG.4a), and in this instance they act as support for the stack 2 a. Thecontainer stack 2 a is lifted from the originally horizontal, short forkarms 27 which move upward, e.g., between the rollers of the rollerconveyor 3 c and tilted into a lying posture, cf. the lying stack 2 inFIG. 4c, the fork arms 26 simultaneously being pivoted into a horizontalposition so that the container stack 2 a is controlledly turned. It nowlies transversely to the conveyor 3 c on a support 3 d, preferably afurther conveyor, in this instance with the container openings 6 bfacing forward (cf. FIG. 4c). The conveyor 3 d then guides the turnedcontainer stack 2 to the denesting device 1′ proper according to FIG. 2.

In FIGS. 5a and 5 b, a device 29 for longitudinally orienting containers6 provided individually as described before and located transversely tothe conveyor 3, is illustrated in side view and in top view,respectively. The containers 6 are advanced by conveyor 3, here, e.g., aroller conveyor, in the direction of arrow IX (FIG. 5a), of which atleast a few of the rollers 30 are driven. At either side of conveyor 3,one guide 31 each is provided so as to guide the containers 6 along theconveyor 3; guides 31 narrow in transport direction until the distancebetween them merely allows for the passage of a longitudinally orientedcontainer 6. In front of this narrowed portion 32, two individuallyupwardly shiftable cylinders 33 a and 33 b, respectively, are adjacentlymounted as stops on the conveyor 3. Depending on the direction in whichcontainer 6 is to be rotated (to be oriented e.g. with a container flapor a bar code on a certain side), the one cylinder, e.g. 33 a, isshifted upwards to above the conveying plane 34, whereas the othercylinder, e.g. 33 b, will remain below the conveying plane 34 or will beretracted so that it will be no impediment for the arriving container 6.The control signal for this actuation of cylinders 33 a, 33 b may comefrom a detector 35 which detects on which side of container 6 thecontainer flap or the barcode is located. In FIG. 5b, the right-handcylinder 33 b viewed in conveying direction (arrow IX in FIG. 5a) hasbeen lowered, whereas the left-hand cylinder 33 a has been pushed upfrom the conveying plane 34. Container 6 which has been transportedthere, on one of its sides—the left-hand side—is held back by upwardlyprotruding cylinder 33 by abutment thereon, whereas theother—right-hand—side of container 6 is free so that container 6 ismoved on by the conveyor 3 under rotation about the stop, i.e. thecylinder 33 a, since the right-hand container side moves faster ascompared to the left-hand container side. Container 6, which has alreadybeen somewhat turned—as apparent from FIG. 5b, then is forced tocompletely longitudinally align in the narrowed portion 32 and is movedon by conveyor 3.

In FIG. 6, a shunting means 36 is shown for distributing the containers6 according to the container height onto two separate conveying paths orconsecutive conveyors 3 e, and 3 f, respectively. Just like the device29 shown in FIG. 5 for longitudinally orienting the container 6, alsothe shunting means 36 comprises two retractable and extendable cylinders33 a and 33 b, respectively, adjacently mounted on the conveyor 3. Acontainer height sensor 37, e.g. with photoelectric barriers which aremounted at certain levels, may sense the height of the passed-bycontainers 6 and send a signal to each of the retractable and extendiblecylinders 33 a and 33 b for extension or retraction, respectively.Simultaneously, a pivotable access lever 38 may be actuated, which, onthe one hand, blocks access to the one consecutive conveyor, e.g. 3 e,and, on the other hand, guides container 6 to the other consecutiveconveyor, e.g. 3 f. In FIG. 6, cylinder 33 a which is located on theleft-hand side in transporting direction X protrudes from the conveyingplane, whereas the right-hand cylinder 33 b has been lowered to belowthe conveying plane 34. This causes container 6 to run up against theleft-hand cylinder 33 a, it being rotated about its own axis. Afterhaving been sufficiently rotated, container 6 is moved past cylinder 33a and gets on the right-hand consecutive conveyor 3 f in the directionof arrow X, the lever or pivot arm 38 assisting this movement andblocking access to the left-hand consecutive conveyor 3 e.

In FIGS. 7a to 7 e, a side view of a further embodiment of a stackturning device 20″ is shown, the course of turning being schematicallyillustrated. The vertical, upright container stack 2 a is advanced onconveyor 3 d to the stack turning device 20″, as has been described inFIG. 4. The stack turning device 20″ in turn has two pairs of fork arms26, 27, the shorter fork arms 27 of the one pair initially beingpresent, according to FIG. 7a, below the stack 2 a advanced for turning,and the other, longer fork arms 26 being pivoted upwards by a pressuremedium cylinder 39 mounted so as to be pivotable about an axle 40 from ahorizontal position present below the conveying plane, into a verticalposition until they abut on the container stack 2 a. In FIG. 7b, thefork arms 26 are shown in this vertical position in contact with thecontainer stack 2 a. A separate pressure medium cylinder 41 providedbelow the horizontal fork arms 27 and also mounted to be pivotable aboutan axle 42 (cf. FIG. 7c) engages these fork arms 27 so that thehorizontal fork arms 27 and thus the container stack 2 a are graduallybrought into a slanted position (FIG. 7c) by extension of the piston rodof the pressure medium cylinder 41, wherein simultaneously the stack 2 aand the fork arms 26 are brought into a slanted position and now aresupported by the pressure medium cylinder 39. The pressure mediumcylinder 39 is gradually retracted during this movement of turning, itbeing simultaneously pivoted about its axle 40. The pressure mediumcylinder 41 likewise is pivoted about its axle 42 and pushes the shorterfork arms 27 upwards at least until the container stack 2 a would startto tilt (i.e. until its center of gravity, viewed in verticalprojection, is no longer present above the base face defined by the forkarms 27). Subsequently, the pressure medium cylinder 41 is retractedagain, and the fork arms 27 are pivoted into the horizontal startingposition (FIG. 7d), while simultaneously the fork arms 26 on which themass of the container stack 2 a now rests gradually are further pivotedtogether with the container stack 2 a and finally also are brought intothe horizontal position (FIG. 7e). Now the turned container stack 2 a ismoved away from the stack turning device 20″ by the conveyors 3 d and 3and towards the arrangement 1 for denesting, where denesting is effectedas described before, e.g. by way of FIG. 1.

In FIG. 8, a modified gripping means 5′ for the arrangement 1 forautomatic denesting of a lying container stack 2, in particular of theembodiment according to FIG. 1, is schematically illustrated on anenlarged scale, wherein merely one side of the gripping means 5′ isshown in more detail as regards its individual parts, in particular agripping jaw unit 45, whereas the other side is partly occluded, yet isof equal construction so that it suffices to explain one side.

Each gripping jaw unit 45 comprises a pressure medium cylinder 46 ofhorizontal orientation which is mounted on a holding means, again in theform of a leg 8 a of a frame 9. A gripping jaw 47 is mounted on a pivotlever 48 actuated by the pressure medium cylinder 46. The pivot lever 48has an upper plate 49 a and a lower plate 49 b between which at one endthe gripping jaw 47 equipped with a friction material (rubber) is held.At the other end, an axle 50 is mounted between plates 49 a, 49 b, atwhich the pressure medium cylinder 46, which is mounted to be pivotableabout an axle 51, engages with its piston rod.

The pivot lever 48 in turn is mounted to be pivotable about a pivot axle52, which is mounted on a bracket 53 that is fixedly attached, e.g.welded, to the respective leg 8 a of frame 9 and also carries thepressure medium cylinder 46 via axle 51.

If the pressure medium cylinder 46 pushes in direction C, while pivotingabout its axle 51, the pivot lever 48 is pivoted in direction D aboutaxle 52. By this movement of the pivot lever 48, the gripping jaw 47 ispressed against the collar-shaped rim 7 of the first container 6 ofcontainer stack 2. Due to the movement of frame 9 already described withrespect to FIG. 1, the first container 6 is then moved away fromcontainer stack 2, this movement acting in the sense of an increase ofthe clamping effect of the gripping jaws 47. By retracting the pressuremedium cylinder 46, the pivot lever 48 is again pivoted into thedirection opposite to direction D so that the gripping jaws 47 againrelease the rim 7 of the first container 6.

What is claimed is:
 1. An arrangement for automatically denestingcontainers conveyed on a horizontal conveyor with container bottomsfacing forward and nested in each other in a container stack in a lyingposture, and for depositing a container on a support with a containeropening facing upwards, the arrangement comprising: pressure grippingmeans for gripping and moving a respective first container of saidcontainer stack, said gripping means having a pair of lateralpressure-medium cylinders, each pressure-medium cylinder of the pairhaving a horizontal axis with the horizontal axes of the pair orientedin a common horizontal plane; holding elements movable in a stackingdirection, said holding elements supporting said gripping means at lowerportions of said holding elements; clamping means for holding back thecontainer stack, with the first container being left free of thecontainer stack; wherein the support is positioned immediately beneathan end of said horizontal conveyor and wherein a denested container ismoved to the end of the conveyor, tilted by gravity about the end of theconveyor and falls onto the support with its container opening facingupward.
 2. An arrangement according to claim 1, characterized in thatthe pressure medium cylinders are rotatably arranged on the holdingelements.
 3. The arrangement according to claim 1, further comprising apressure medium cylinder for driving the holding elements in thestacking direction.
 4. The arrangement according to claim 1, whereinsaid gripping means comprise a pair of gripping jaws which are pressedagainst the first container, each gripping jaw being attached to arespective pivoting lever actuated by a respective pressure mediumcylinder.
 5. An arrangement according to claim 1, characterized in thatthe holding elements are mounted to be linearly displaceable in parallelto the container stack.
 6. The arrangement according to claim 5, whereinthe holding elements are mounted on a linear guide.
 7. The arrangementaccording to claim 1, further comprising a shunting means fordistributing denested containers to one of a plurality of conveyingpaths according to container height.
 8. The arrangement according toclaim 7, further comprising vertically arranged photoelectric barriersfor sensing container height as a container moves on the horizontalconveyor toward the shunting means.
 9. The arrangement according toclaim 1, wherein said clamping means comprises a pressure mediumcylinder which pushes at least a second container in the container stackdownwards and a lifting mechanism which lifts the container stack offthe horizontal conveyor.
 10. The arrangement according to claim 9,wherein said clamping means further comprises a stop which is pivotedout of engagement with the container stack.
 11. The arrangementaccording to claim 10, further comprising a trigger photoelectricbarrier for actuating one of the clamping means pressure medium cylinderor the stop.
 12. The arrangement according to claim 1, furthercomprising a pneumatically-actuated stack turning device for handlingcontainer stacks prior to feeding the container stacks to the grippingmeans.
 13. The arrangement according to claim 12, wherein said stackturning device comprises a stack sliding support which is verticallyoriented in a resting position and is pivotable about a horizontal axis.14. The arrangement according to claim 13, further comprising a standand a roller mounted on the stand and extending opposite said stacksliding support, said roller controlling movement of a container stackas the container stack is pivoted into a horizontal position.
 15. Anarrangement according to claim 1, characterized in that a monitoringphotoelectric barrier is provided for sensing the remaining containersof the stack.
 16. The arrangement according to claim 15, furthercomprising angled forked arms pivotally mounted on the stack turningdevice to pivot about a horizontal angle axis.
 17. The arrangementaccording to claim 15, wherein the stack turning device comprises a pairof supporting devices for supporting the container stack and pressuremedium cylinders for pivoting the one of the pair of supporting devicesindependently of the other.
 18. The arrangement according to claim 1,further comprising a container rotating device for rotating the firstcontainer from a transverse orientation into a longitudinal orientation.19. An arrangement according to claim 18, characterized in that thecontainer rotating device has an associated control unit for rotatingeach container with a predetermined side facing forward.
 20. Thearrangement according to claim 18, wherein the container rotating devicecomprises two stop cylinders selectively projectable vertically abovethe conveying plane of the horizontal conveyor, the width of thehorizontal conveyor narrowing at a location downstream from the stopcylinders.
 21. An arrangement for automatically denesting containersconveyed on a horizontal conveyor with container openings facing forwardand nested in each other in a container stack in a lying posture, andfor depositing a container on a support with the container openingfacing upwards, the arrangement comprising: pressure gripping means forgripping and moving a respective foremost container of said containerstack, said gripping means having a pair of lateral pressure-mediumcylinders, each pressure-medium cylinder of the pair having a horizontalaxis with the horizontal axes of the pair oriented in a commonhorizontal plane; holding elements movable in a stacking direction, saidholding elements supporting said gripping means at lower portions ofsaid holding elements; clamping means for holding back the containerstack, with the foremost container being left free of the containerstack; and movement control means for controlling the movement of theholding elements so as to move the foremost container out of thecontainer stack, to pivot the foremost container and to deposit theforemost container onto the support with its container opening facingupwards.
 22. An arrangement according to claim 21, characterized in thatthe holding elements have an associated connecting-link guide forcontrol of their movement.
 23. An arrangement according to claim 21,characterized in that the holding elements have an associated four-barlinkage for control of their movement.
 24. The arrangement according toclaim 21, further comprising a pressure medium cylinder for driving theholding elements in the stacking direction.
 25. The arrangementaccording to claim 21, wherein said gripping means comprise a pair ofgripping jaws which are pressed against the foremost container, eachgripping jaw being attached to a respective pivoting lever actuated by arespective pressure medium cylinder.
 26. An arrangement according toclaim 21, characterized in that a monitoring photoelectric barrier isprovided for sensing the remaining containers of the stack.
 27. Thearrangement according to claim 21, further comprising a shunting meansfor distributing denested containers to one of a plurality of conveyingpaths according to container height.
 28. The arrangement according toclaim 21, further comprising vertically arranged photoelectric barriersfor sensing container height as a container moves on the horizontalconveyor toward the shunting means.
 29. The arrangement according toclaim 21, wherein the holding elements are pivotally mounted on a frame.30. The arrangement according to claim 29, wherein said clamping meanscomprises a pressure medium cylinder which pushes at least a secondcontainer in the container stack downwards and a lifting mechanism whichlifts the container stack off the horizontal conveyor.
 31. Thearrangement according to claim 30, wherein said clamping means furthercomprises a stop which is pivoted out of engagement with the containerstack.
 32. The arrangement according to claim 31, further comprising atrigger photoelectric barrier for actuating one of the clamping meanspressure medium cylinder or the stop.
 33. The arrangement according toclaim 21, further comprising a container rotating device for rotatingthe foremost container from a transverse orientation into a longitudinalorientation.
 34. An arrangement according to claim 33, characterized inthat the container rotating device has an associated control unit forrotating each container with a pre-determined side fang forward.
 35. Thearrangement according to claim 33, wherein the container rotating devicecomprises two stop cylinders selectively projectable vertically abovethe conveying plane of the horizontal conveyor, the width of thehorizontal conveyor narrowing at a location downstream from the stopcylinders.
 36. The arrangement according to claim 21, further comprisinga pneumatically-actuated stack turning device for handling containerstacks prior to feeding the container stacks to the gripping means. 37.The arrangement according to claim 36, wherein said stack turning devicecomprises a stack sliding support which is vertically oriented in aresting position and is pivotable about a horizontal axis.
 38. Thearrangement according to claim 36, further comprising a stand and aroller mounted on the stand and extending opposite said stack slidingsupport, said roller controlling movement of a container stack as thecontainer stack is pivoted into a horizontal position.
 39. Thearrangement according to claim 36, further comprising angled forked armspivotally mounted on the stack turning device to pivot about ahorizontal angle axis.
 40. The arrangement according to claim 36,wherein the stack turning device comprises a pair of supporting devicesfor supporting the container stack and pressure medium cylinders forpivoting the one of the pair of supporting devices independently of theother.